Mycobacterium avium is a representative of a large group of mycobacteria which are widely distributed in nature, have pathogenic capabilities, and are resistant to nearly all currently available drugs. This group includes M. intracellulare and M. scrofulaceum and together the three mycobacteria comprise the MAIS complex. Synchronized cells of M. avium can be obtained by selective filtration. The synchronized cells elongate over a period of 40 hours and then undergo rapid cell fission for an additional 40 hours of incubation. The cell growth and the cell fission stages possess fundamentally different metabolic activities. These activities will be quantitated with emphasis placed on the synthesis and activity of enzymes involved in nitrogen metabolism, in utilization of fatty acid, and in triglyceride turnover and sulfolipid synthesis. The goal of this project is to determine the potential drug sensitive sites that M. avium may have. Physiologic activities will be determined for the cells maintained in either the elongation state or in the rapidly dividing state by continuous culture and continuous phase techniques. This experimental approach will be used to pinpoint metabolic sites unique to the growth and division of M. avium, and the effect of drugs on these activities will then be assessed. Other isolates, belonging to the MAIS complex, will be screened to determine whether they possess physiologic features similar to those discovered for M. avium.